Specific Cellular Defences Flashcards
What is immune surveillance?
When types of white blood cells travel around the body to monitor the state of the tissues
What happens if a white blood cell spots a damaged piece of tissue
The white blood cells will release cytokines into the blood
What is the effect of cytokines
To increase blood flow therefore allowing specific white blood cells to accumulate at the site of infection
What is an antigen
An antigen is a foreign molecule that is recognised by a lymphocyte and causes a specific response
What do lymphocytes have that attracts antigens
Lymphocytes have several copies of single type antigen receptors
What happens when a lymphocyte binds to an antigen
It goes through cell division to form a large population of identical lymphocytes
What is the large population of identical lymphocytes called
Clonal population
- the process is known as clonal selection
What are the two types of lymphocytes
T-lymphocytes
B- lymphocytes
How to T-lymphocytes distinguish between cells
They have specific proteins that can tell the difference between the body’s own cells and foreign cells
What is autoimmunity
When the body no longer tolerates self molecules and T-lymphocytes attacking their own body cells
What is an allergy
It is a hypersensitive response by B- lymphocytes to an antigen that is harmless
What are the two groups of T-lymphocytes
Helper T cells -
secrete cytokines and activate B-lymphocytes and phagocytes
Cytotoxic T cells -
Destroy infected cells by apoptosis
What do phagocytes do when pathogens infect tissues
Some Phagocytes present fragments of the pathogens antibodies at its surface
This is used to produce clone T lymphocytes that move to the site of infection under direction of cytokines
These are known as antigen presenting cells
Immunological memory-
A primary response
Is when a person is first infected and responds by producing antibodies
Immunological memory -
A secondary response
When a person is infected by the same antigen for a second time and produces antibodies
